1. Field of the Invention
Broadly speaking, this invention relates to aviation. More particularly, in a preferred embodiment, this invention relates to methods and apparatus for guiding and controlling aircraft in a landing zone.
2. Discussion of the Prior Art
The difficulties of safely landing aircraft have been widely reported. When the environment is hostile, for example, in a tactical military situation, or where traffic congestion exists or the weather is marginal, the pressure on the pilot and on the traffic controller often leads to dangerous situations, if not to fatal accidents.
As a solution to these problems, a new generation of landing systems has been developed. Known generically as Microwave Landing Systems (MLS), these systems typically comprise a localizer transmitter which generates a localizer beam indicating to the pilot where he is with respect to the desired lateral flight path, a DME transmitter which permits an onboard computer to determine how far the aircraft is from the DME transmitter and a glideslope transmitter which indicates to the pilot where he is, in terms of a vertical angle, with respect to the landing zone. Some MLS systems are portable and can be fully deployed by only two men in less than an hour. Thus, in a tactical military situation, for example, a clearing can be made in the jungle and the MLS equipment deployed before the enemy can take effective countermeasures, with obvious advantages.
As effective as such MLS systems are, they by themselves do not fully solve the problems of efficient aircraft guidance and control in the terminal area, particularly the funneling of a plurality of incoming aircraft into the landing pattern. The problem, then, is to devise a scheme for such control and guidance which is compatible with MLS landing systems and, indeed, which permits maximum utilization of MLS capabilities.